|Publication number||US5878581 A|
|Application number||US 08/957,886|
|Publication date||Mar 9, 1999|
|Filing date||Oct 27, 1997|
|Priority date||Oct 27, 1997|
|Publication number||08957886, 957886, US 5878581 A, US 5878581A, US-A-5878581, US5878581 A, US5878581A|
|Inventors||Larry DeFrances, Larry J. Gaudino|
|Original Assignee||Advanced Metallurgy Incorporated|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (2), Referenced by (11), Classifications (6), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
This invention relates to new and improved heat exchanger systems and methods in which the endothermic potential of the evaporation of liquified gas such as nitrogen is used to cool process cooling water.
2. Prior Art
In industrial plants and processes, cooling fluid such as water often is needed. Cooling of such fluids most often is accomplished by the use of radiator-type cooling systems. Unless such systems are designed to accommodate the most severe requirement, e.g. during the hottest days of summer, varying quantities of city water may have to be used to supplement the cooling capacity of the closed cooling system. Such excess amounts of cooling water must be discharged from the system, e.g. to the sewer. However, many governmental regulations prohibit such disposal of cooling fluid, necessitating that the fluid be discharged into on-site treatment facilities. The accompanying expense is unattractive. Over-designing the radiator-type cooling system for assuring necessary cooling capability for, perhaps, only a few days per year is costly in terms of both capital investment and operating expenses.
Closed loop heat exchangers are known in which a first cold fluid in a closed loop functions to lower the temperature of a second cooling fluid.
Many industrial facilities requiring the use of cooling fluids also entail the use of nitrogen or other liquefiable gases wherein the conversion of such gases from liquid form, in which the gas is stored, to gaseous form is endothermic. The present invention takes advantage of the endothermic nature of evaporation of liquified gas, such as nitrogen, as a primary coolant, by gasifying the fluid in a first loop coil immersed in a secondary coolant fluid-filled heat exchanger vessel to reduce the temperature of the secondary coolant in a second loop in the heat exchanger, and passing the cooled secondary coolant to a reservoir from which cooled secondary coolant is passed in a third loop to relevant equipment and processes and from which reservoir heated secondary coolant is returned, through the second loop, to the heat exchanger.
The single drawing is a schematic illustration of the invention in side elevation showing the several loops and associated tanks and the directions and illustrative temperatures of the several streams of warm and cold secondary cooling fluid and the primary liquid and gaseous cooling fluid.
In the FIGURE, the numeral 1 denotes a heat exchanger, which may take the form of a generally cylindrical vessel, containing a heat exchange medium, such as water, and in which is immersed a coil 2 as part of a first loop for introduction into heat exchanger 1 of liquid primary coolant, such as nitrogen, from a bulk cryogenic storage tank (not shown) for expansion from liquid to gaseous form in the coil 2 and, due to the endothermic nature of evaporation and expansion in coil 2 of the liquid to gaseous primary coolant, reducing the temperature of a secondary coolant, such as water, in a coil 3 of a second loop which connects with a liquid reservoir 4 and which carries cooled secondary coolant via the second loop from the heat exchanger 1 to the reservoir 4.
The first loop leaves the heat exchanger 1 through a line 6 and carries the gasified primary coolant to process equipment as needed.
The second loop exits the heat exchanger 1 through a line 7, with the secondary coolant at a relative cool temperature, e.g. about 58°-65° F., and line 7 enters the reservoir 4 from the top of the vessel and one end extends to near the bottom of the reservoir as shown at 8 in the drawing.
The third loop comprises a line 9 extending inside the reservoir to an end 11 at a depth approximately that of end 8 of line 7 of the second loop, leaves the top of the reservoir 4, passing through a pump 12, and, with the secondary coolant at a needed cooling temperature, e.g. about 62°-70° F., passes to the relevant equipment and processes. The third loop is completed with the return of warmed secondary coolant from the relevant equipment and processes at an elevated temperature, e.g. about 85°-100° F., through a line 13 which enters the top of reservoir 4 and extends to an end 14 located just above the fluid level in reservoir 4. Optimally, a flat baffle plate 16 is positioned below the end 14 of line 13 to better distribute, over at least a substantial portion of the surface of the liquid in the reservoir 4, the warmed secondary coolant in its return to the reservoir. By virtue of such construction and operation of the system of the invention, there is established a temperature gradient in the reservoir 4, from warmer condition of the secondary coolant near the top of the reservoir, to a cooler condition near the bottom of the reservoir.
The second loop is completed by a line 17 exiting the top of reservoir 4 and having an end 18 disposed in the reservoir just under the surface of the secondary fluid therein, passing through a second pump 19, and continuing on to enter the heat exchanger vessel 1 and form coil 3 disposed below the liquid-to-gas expansion coil 2.
Exemplarily, the primary coolant is nitrogen and the heat exchange medium and the secondary coolant is water. In a specific example, using such equipment and with approximately 270,000 gallons of liquid nitrogen available for process and/or equipment cooling needs, there are over 182 million cooling BTUs available from expansion of the liquid nitrogen into gaseous form. It takes about 250 BTUs of cooling to chill ten pounds of water by 25° F., and, considering external cooling losses, such a nitrogen supply provides enough cooling to chill 8000 gallons of water 25° F. In such case reservoir 4 may have a volume of about 8000 gallons, and heat exchanger 1 may have a volume of about 500 gallons. In such a system, end 18 of line 17 in the second loop is disposed about one foot below the water level in reservoir 4; end 8 of line 7 is disposed about 8 feet below the water level in the reservoir; the end 11 of line 13 is disposed about 9 feet below the water level in the reservoir, and end 14 of line 13 is disposed about one foot above the water level in the reservoir 4.
Accordingly, in a facility needing cooling water and a substantial amount of nitrogen coolant, this invention avoids the wasteful loss to the atmosphere of cooling BTUs inherent in the evaporation of nitrogen by using those BTUs for cooling water and thus further reducing costs by avoiding the need for over-designed or supplemental conventional cooling means.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3672182 *||Jun 25, 1970||Jun 27, 1972||Air Prod & Chem||Water cooling method and apparatus employing liquid nitrogen|
|US4464904 *||May 19, 1983||Aug 14, 1984||Union Carbide Corporation||Process for the transfer of refrigeration|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US6347523 *||Nov 28, 2000||Feb 19, 2002||The Coca-Cola Company||Apparatus using stirling cooler system and methods of use|
|US6347524||Nov 28, 2000||Feb 19, 2002||The Coca-Cola Company||Apparatus using stirling cooler system and methods of use|
|US6378313||Jul 23, 2001||Apr 30, 2002||The Coca-Cola Company||Apparatus using Stirling cooler system and methods of use|
|US6470690 *||May 12, 1999||Oct 29, 2002||Exta Exclusive Thermodynamic Applications Ltd.||Method and apparatus for supplying vaporized gas on consumer demand|
|US6532749||Jul 27, 2001||Mar 18, 2003||The Coca-Cola Company||Stirling-based heating and cooling device|
|US6550255||Mar 21, 2001||Apr 22, 2003||The Coca-Cola Company||Stirling refrigeration system with a thermosiphon heat exchanger|
|US6581389||Mar 21, 2001||Jun 24, 2003||The Coca-Cola Company||Merchandiser using slide-out stirling refrigeration deck|
|US6675588||Mar 21, 2001||Jan 13, 2004||The Coca-Cola Company||Apparatus using stirling cooler system and methods of use|
|US20140116663 *||Jun 25, 2012||May 1, 2014||Taiyo Nippon Sanso Corporation||Heat exchanger|
|WO1999058896A2 *||May 12, 1999||Nov 18, 1999||Eta Exclusive Thermodynamics Applications Ltd.||Method and apparatus for supplying vaporized gas on consumer demand|
|WO1999058896A3 *||May 12, 1999||Mar 9, 2000||Gadi Sicherman||Method and apparatus for supplying vaporized gas on consumer demand|
|U.S. Classification||62/50.2, 62/434|
|Cooperative Classification||F25D17/02, F25D3/10|
|Oct 27, 1997||AS||Assignment|
Owner name: ADVANCED METALLURGY INCORPORATED, PENNSYLVANIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:DEFRANCES, LARRY;GAUDINO, LARRY J.;REEL/FRAME:008873/0372
Effective date: 19971020
|Sep 25, 2002||REMI||Maintenance fee reminder mailed|
|Mar 10, 2003||LAPS||Lapse for failure to pay maintenance fees|
|May 6, 2003||FP||Expired due to failure to pay maintenance fee|
Effective date: 20030309